An insect among living things present in the natural world has compound eyes. The compound eye consists of a number of ommatidia arranged in a spherical shape. In other words, the ommatidium is a unit configuring the compound eye. Here, the respective channels (ommatidia) are directed toward slightly different directions, and receive only signals incident within a predetermined range in relation to optical axes of the channels to form a final image.
This structure has a wide field of view, may sense rapid movement, and is advantageous in miniaturization. Therefore, recently, many miniaturized optical sensors inspired by a visual structure of the insect have been developed.
Particularly, recently, a demand for compact and ultrathin cameras has increased. However, there is a limitation in miniaturizing conventional lens designs. Therefore, an imaging system inspired by the eye of the insect has been prominent as an alternative to the existing imaging systems.
As a technology related to the imaging system inspired by the eye of the insect, there is a scientific treatise entitled “Digital cameras with designs inspired by the arthropod eye” (author: Young Min Song, Yizhu Xie, Viktor Malyarchuk, Jianliang Xiao, Inhwa Jung, Ki-Joong Choi, Zhuangjian Liu, Hyunsung Park, Chaofeng Lu, Rak-Hwan Kim, Rui Li, Kenneth B. Crozier, Yonggang Huang and John A. Rogers, journal: Nature, Vol. 497 on May, 2013).
Meanwhile, FIG. 1 is a view illustrating an ommatidium of an eye of a natural insect.
Each ommatidium includes a facet lens 11 receiving light, a rhabdom 13 guiding the light incident through the facet lens 11, a crystalline cone 12 connecting the facet lens 11 and the rhabdom 13 to each other, and a photoreceptor cell 14 sensing the light. Here, one ommatidium senses only light incident within a predetermined range from a direction toward which it is directed.
The optical sensor inspired by the structure of the eye of the insect as described above has the same advantage as an advantage of the eye of the insect, such that it may more accurately sense a range wider than those of existing distance and position sensors. Therefore, an invention for the optical sensor inspired by the structure of the eye of the insect has been demanded.